What it means
The bank 1 sensor 2 oxygen sensor pumping current trim circuit is open or faulty. The code does not by itself establish that the circuit carries a per-sensor calibration code.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
Bank 1 Sensor 2 is the downstream oxygen sensor on the bank containing cylinder 1. The control module monitors the sensor's pumping-current trim circuit, which is part of the wide-band sensor control system; this code sets when that circuit is open or otherwise faulty and does not establish that it carries a per-sensor calibration code.
Common causes
Most likely first.
- Open trim line
- Pin pushed back out of connector body
- Cracked solder joint inside the module or sensor
Symptoms
- Check engine light on
- Increased fuel consumption
- Possible rough idle or hesitation
- Failed emissions test
How to diagnose it
- Save freeze-frame data and check live Bank 1 Sensor 2 readings for evidence that the trim circuit fault is active.
- Inspect the trim-circuit wire and connector for breaks, corrosion, heat damage, or a pin pushed back into the connector body.
- Use the wiring diagram to trace the trim line and check continuity with the manufacturer's procedure.
- Check connector pin retention and terminal contact at the sensor and module ends of the circuit.
- If the external line is intact, use the manufacturer's tests to isolate an internal sensor or module fault.
Common fixes
- Reseat and secure a displaced Bank 1 Sensor 2 connector pin.
- Repair an open or damaged pumping-current trim wire.
- Restore clean, secure contact at corroded or loose terminals.
- Replace the sensor or repair the module only if testing confirms an internal failure.
Can I keep driving?
If the engine runs normally and the check-engine light is steady, limit driving and arrange diagnosis soon. The downstream sensor may not be controlled or monitored correctly, potentially affecting fuel economy and emissions compliance.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.